Emerging Biofabrication Strategies for Engineering Complex Tissue Constructs

The demand for organ transplantation and repair, coupled with a shortage of available donors, poses an urgent clinical need for the development of innovative treatment strategies for long‐term repair and regeneration of injured or diseased tissues and organs. Bioengineering organs, by growing patient‐derived cells in biomaterial scaffolds in the presence of pertinent physicochemical signals, provides a promising solution to meet this demand. However, recapitulating the structural and cytoarchitectural complexities of native tissues in vitro remains a significant challenge to be addressed. Through tremendous efforts over the past decade, several innovative biofabrication strategies have been developed to overcome these challenges. This review highlights recent work on emerging three‐dimensional bioprinting and textile techniques, compares the advantages and shortcomings of these approaches, outlines the use of common biomaterials and advanced hybrid scaffolds, and describes several design considerations including the structural, physical, biological, and economical parameters that are crucial for the fabrication of functional, complex, engineered tissues. Finally, the applications of these biofabrication strategies in neural, skin, connective, and muscle tissue engineering are explored.     

A novel SOI MESFET to spread the potential contours towards the drain

ABSTRACT

This paper presents a new structure of Metal Semiconductor Field Effect Transistor (MESFET) for high power applications. One of the problems that we face in the design of the MESFET devices is that in most cases, the increase of breakdown voltage is accompanied by a decrease in the saturation drain current. Our aim to propose this structure is to improve these two parameters simultaneously. Using the insulator region under the sides of the gate (IR) and the hide field plate (HFP) in the buried oxide (BOX) are the fundamental solution for improving these parameters. We named the proposed structure as spread potential contours towards the drain MESFET (SPC-MESFET). By applying the proposed structure, the drain current and the breakdown voltage improve 20 and 27 percent compared to a conventional structure (C-MESFET), respectively. Therefore, the proposed device has a higher maximum power density than the C-MESFET structure. Also, this idea reduces the gate capacitance and thus the frequency characteristics such as cut off frequency (f_T), maximum oscillation frequency (f_max), and Maximum Available Gain (MAG) improve in comparison with the C-MESFET structure.     

Investigating on performance parameters and flow field of centrifugal compressor based on the splitter blade leading edge’s location effect

Impeller design in turbomachines is one of the most challenging issues in these machines’ systems, which still plays a significant role in their efficiency and performance. This article considers different designs for splitter blades. Therefore, the CFD methods modify the position of the splitter blades leading edge at the hub and shroud. This modification shall lead to a different splitter blade profile from the main blades. Then, the effects of splitter blades are discussed, and the performance parameters have also been studied to improve this method’s implementation. The results revealed that the compressor’s efficiency was improved by approximately 1.5 % in one specific case. This finding proves that the previous design methods were not the optimum ones for compressors and how to increase the compressor’s efficiency by CFD methods and by changing the splitter blades’ location.

     

A Novel SOI MESFET to Improve the Equipotential Contour Distributions by Using an Oxide Barrier

Silicon - A new Metal Semiconductor Field Effect Transistor (MESFET) structure in Silicon on Insulator (SOI) technology will be introduced in this paper. In our idea, an oxide barrier is used on...     

Development and characterization of flexible antenna based on conductive metal pattern on polyester fabric

Current paper focuses on the development and characterization of flexible antenna based on conductive metal pattern on polyester fabric. The flexible fabric patch antenna was prepared by printing of metallic patterns on fabric textures through a multi-step process. The inkjet printing followed by electroless nickel plating methods were employed to coat different patch sizes and shapes with extremely high conductivity on insulated fabric. The scanning electron micrograph imaging technique confirms the formation of Ni nanoparticle with normal distribution and average size of 150 ± 20 nm. The EDAX analysis reveals more than 93%w/w Ni which supports the high four-point probe conductivity of 2500 ± 175 S/cm for antenna patterns. The X-ray diffraction pattern also indicates the amorphous nickel formation and randomly phosphorus atoms trapped between the nickel atoms. Also, the measured results evidence that the tensile strength of the textile Antenna shows an increase of 25.72% in the warp direction and 19.98% in the weft direction. Also the amount of flexural stiffness significantly improves and the wrinkles reduced after electroless plating. Also the antenna’s gain and bandwidth were studied by spectrum analyzer and the coated film surfaces. The largest printed patch antenna experienced a significant increase of about 1 kHz in bandwidth and ?3 dB increase in gain value compared to other antennas. Also, the rectangular shape antenna showed a peak value at bandwidth of 4.2 kHz and gain value of ?0.1 dB in comparison with spiral antenna.